Class 12th

$\omega =2\pi f=2\pi *50=100\pi$

$X_L=wL=100\pi *100*10^{-3}$

$X_C=\frac{1}{wC}=\frac{1}{100\pi }*100*10^{-6}=\frac{100}{\pi }$

$z=10.0086\Omega$

$l=\frac{v}{z}=\frac{220}{10.008}=22A$

Benzoic acid & naphthalene can be separated by crystallization. Benzoic acid is soluble is hot water but naphthalene is insoluble.

Assertion is incorrect & Reason is correct.

volume of wire will remains constant

$\pi r_1^2{\mathcal{l}}_1=\pi r_2^2{\mathcal{l}}_2$

$\Rightarrow {\mathcal{l}}_2=2{\mathcal{l}}_1\left(Given\right)$

$r_2=\frac{r_1}{\sqrt[]{2}}$

$R_2=\frac{\rho {\mathcal{l}}_2}{\pi r_2^2}=\frac{\rho 2{\mathcal{l}}_1}{\pi {\left(\frac{r_1}{\sqrt[]{2}}\right)}^2}$

$=\frac{R_2-R_1}{R_1}*100=\frac{4R_1-R_1}{R_1}*100=\frac{3R_1}{R_1}*100=300\mathrm{\%}$

Assertion : Clean water has BOD less than 5ppm. Highly polluted water has BOD greater than or equal to 17 ppm.

Reason : BOD is measure of oxygen required to oxidize only bio-degradable organic matter.

Thus Assertion (A) is correct & Reason (R) is wrong.

Volume of 27 identical drops = volume of a bigger drop

$\Rightarrow 27*\frac{4}{3}\pi r^3=\frac{4}{3}\pi R^3$              

R³ = 27r³

R = 3r

Given potential of a small drop = 22v

$V_{bigger}=\frac{k\left(27q\right)}{R}=\frac{27kq}{3r}=9\frac{kq}{r}=9*22=198volt$

the lowest spin only magnetic moment for Ni⁺² because of minimum unpaired electron.

$Pb{\left(N{O}_3\right)}_2\underset{673K}{\overset{\Delta }{\to }}PbO+\underset{\left(A\right)}{N{O}_2}+O_2$

$\underset{\left(A\right)}{N{O}_2}\underset{}{\overset{Dimerise}{\to }}\underset{\left(B\right)}{N_2{O}_4}$

$E_{C{\mathcal{l}}_2/C{\mathcal{l}}^{-}}^0=+1.36V$

$E_{l_2/l^{-}}^0=+0.54V$

$E_{A{g}^{+}/Ag}^0=+0.80V$

$E_{N{a}^{+}/Na}^0=-2.71V$

$E_{L{i}^{+}/Li}^0=-3.05V$

$\therefore E_{C{\mathcal{l}}_2/C{\mathcal{l}}^{-}}^0>E_{A{g}^{+}/Ag}^0>E_{N{a}^{+}/Na}^0>E_{L{i}^{+}/Li}^0$

In electro-refining, impure metal (blister copper) is used as an anode while precious metal like Au, Pt gets deposited as anode mud.

Zymase naturally occurs in yeast.

Diastase is found in malt.

Urease is found in soyabean.

Pepsin is found in stomach.